-LRB- CNN -RRB- -- The 2013 tennis season may only be in its fledgling stages but already the heat is well and truly on for those preparing for the year 's first major .

As the great and good on the men 's and women 's circuits fine tune their game ahead of the Australian Open that starts in Melbourne on Monday , they are having to contend with stifling temperatures in Sydney .

According to the Australia Bureau of Meteorology , Monday was the hottest day in the country since records began over 100 years ago with an average temperature of 40.3 degrees .

Officials in New South Wales have warned of a `` catastrophic '' fire threat as strong winds combine with the heat to increase the danger of bushfires spreading out of control .

Players had to battle heat that reached 41.4 deg in Sydney , with world No. 4 Agnieszka Radwanska claiming it was `` too hot '' to play and that officials should have halted proceedings under their extreme heat policy .

But the Pole , along with the other players scheduled on Tuesday , battled through the searing sunshine with the help of regular breaks , ice towels and gallons of liquid .

`` I think this is too hot to play tennis , '' Radwanska told reporters at a press conference . `` Even for players , for ball kids , for even the people sitting out there , I think it 's just too hot . ''

One saving grace for Radwanska was her quick 6-4 6-3 victory over Japan 's Kimiko Date-Krumm which meant she was only on court for 68 minutes .

Russia 's Svetlana Kuznetsova battled through to a 7-6 1-6 6-2 victory over former world No. 1 Caroline Wozniacki , though both players benefited from a heat break before contesting the deciding set .

Kuznetsova told reporters : `` I think it shows you one more time how tough the tennis is right now . How players have to be fit to play in the hot conditions , the windy conditions . We 're like iron women almost .

`` It was very hot out there . In the second set the heat definitely disturbed me a lot . But the break really helped me before the third set . ''

The 2011 French Open champion , Li Na of China , was quoted as saying by AFP that she felt like she was `` playing in a sauna . ''

Germany 's Angelique Kerber triumphed 6-2 7-5 over Russian qualifier Galina Voskoboeva who took a medical time out because of the extreme heat .

Kerber : `` It was unbelievably hot . Usually I practice before my matches , 30 to 35 minutes , today it was just 10 or 15 minutes because I could n't play more . It 's tough to play in these conditions .

`` I was trying to focus on the next point and not thinking about the heat , the sun and the weather . The whole match was tough from the first point . I 'm happy I won in two sets . ''

Temperatures were due to cool off for Wednesday 's play but by the end of the week the thermometer will be back up to 37 degrees in Melbourne , according to Jenny Harrison from the CNN Weather Center .

She told CNN 's World Sport show : `` We do see this every couple of years but this is record-breaking heat . Monday has been confirmed as the hottest day across Australia since records began .

`` It looks as if Tuesday , once we get the stats in , could be the hottest day and outdo Monday .

`` What has happened in the last few hours is a front has come through across the south east of Australia . In literally an hour the temperature in Sydney has dropped more than 10 degrees .

`` Melbourne is cooler than that as the front went through there first . But in Melbourne by the end of the week the temperature is going to rise again , getting well above average . ''

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Record temperatures hit Australia during tennis tournament in Sydney

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Stifling heat of 41.4 degrees make conditions uncomfortable for players

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World No. 4 Agnieszka Radwanska claims it was `` too hot '' to play

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Monday confirmed by Australia Bureau of Meteorology as hottest since records began